DE3006849C2 - Blood collection device - Google Patents

Description

The invention relates to a blood sampling device with a cylinder open at one end and a airtightly displaceable piston therein, the piston rod of which is in a central opening of the partially closed other end of the cylinder is guided and removable, and with one removable in the open end of the cylinder used cover, which has a pierced connection piece on its transverse wall for Possessing a cannula.

Blood sampling devices of this type are known in various embodiments (DE-PS 56 561, 25 33 256, DE-AS 26 53 206). So that the withdrawn blood does not coagulate in the device It is necessary to fill the blood sampling device with a reagent that inhibits coagulation beforehand. A known anticoagulant is, for example, liquid sodium citrate, which is preferred is used when the clotting time of the blood sample, the so-called "Quick value", is to be determined. For this examination it is very important that the liquid anticoagulant is precisely dosed in the Blood collection device is included and its amount and composition during transport and storage is not changed, so that the original coagulation time can be determined State restored, for example, by adding a certain amount of calcium thromboplastin can be. For this reason, the blood collection device must be designed so that it the amount and the composition of the bottled anticoagulant keeps constant and also when the Cannula is not lost before blood collection. For this purpose, DE-AS 26 53 206 is proposed been to close the connection piece for the cannula with a tearable film and this only briefly pierce before inserting the cannula. With this measure it is true that the anticoagulant can evaporate can be prevented until the foil is broken, but the one in the capillary of the connecting piece Anticoagulants that have been sucked up can already be absorbed when the foil is pierced under the prevailing inside Partial release of vapor pressure before the cannula has been attached. That is why this one is well known Blood sampling device not suitable for keeping the anticoagulant constant

From DE-GM 77 31 917 a blood sampling device of a different construction is known, consisting from a cylindrical tube open on one side with one attached to the bottom inside and one from one Annular space surrounded spacer and a piston connected to a piston rod. At this known blood sampling device, the spacer has a longitudinal bore at the bottom of the cylinder, which opens into a connection piece for the cannula set on the outside of the bottom, and at the lower end of the Piston, a plug engaging in the longitudinal bore of the spacer is provided. The anticoagulant can be filled into the annular space surrounding the spacer and there after Insertion of the piston to be kept in reserve. In this known blood sampling device, it is However, it is difficult to get the liquid anticoagulant into the das To fill the spacer surrounding the annular space without this or when the subsequent insertion of the Something is lost in the piston. A dosage of the anticoagulant with a machine is at this construction is hardly possible.

Proceeding from this, the invention is based on the object of providing a blood sampling device of the initially described to create described genus, in which a liquid anticoagulant can be filled automatically and the connecting piece for the cannula is closed so that the anticoagulant is in storage or does not evaporate during transport or get into the capillary of the connecting piece until the cannula has been put on before the intended use.

This problem is solved by a insert that can be inserted into the connection piece of the cover from the inside Stopper which protrudes from the connection piece with a release pin.

In a practical embodiment, the plug can be inserted into the connecting piece with a cone engage and be supported with a collar or shoulder on the inside of the transverse wall of the lid, so that it is held in a precisely defined position until the cannula is attached.

Furthermore, it has proven to be expedient to have the plug with a mounting pin at its inner end to be provided, which is flush with the inner end of the lid. That way it is possible to insert the stopper with its release pin loosely into the capillary of the connecting piece and through Placing the lid with its inner edge on a flat surface the stopper in the final

Push in the closed position. The connection piece can then be closed with a cap until the blood sampling device is used as intended into which the release pin protrudes without contact.

Finally, it is also proposed that the stopper be made of a plastic whose specific Weight is greater than that of blood, so that the stopper wetted with the anticoagulant is completely in the Blood sample is immersed and the anticoagulant can be rinsed from the blood.

A blood sampling device designed according to the invention initially has the advantage that the dosage of the liquid anticoagulant after inserting the piston into the cylinder through the opening of the Cylinder can be done and therefore does not represent a difficult manipulation, so that an automatic machine for the Dosage is usable The decisive advantage is that the liquid anticoagulant after the cylinder has been closed with the cover, its removal nozzle through the inventive trained and arranged stopper has been closed absolutely tightly until the intended use Use of the blood collection device, i.e. also during transport and longer storage, can be kept constant without small amounts being sucked into the capillary of the connecting piece can be. Only immediately before the intended use when putting on the The cannula is the stopper designed and arranged according to the invention with the one molded onto the cannula Connection cone pressed into the blood sampling device and thus out of the connection stub solved. Because with this manipulation, the blood collection device automatically with the lid facing up pointing is held in one hand while the cannula is pushed open by the other hand, it is ruled out that even the smallest amounts of the anticoagulant can escape. Even after The anticoagulant cannot escape during the time it takes for the needle to be inserted into the vein the vapor pressure in the blood sampling device is already reduced when the plug is loosened in the upright position has relaxed through the cannula and the anticoagulant when pivoting the blood sampling device can no longer push outwards with the cannula pointing downwards.

Further details and advantages of the subject matter of the invention emerge from the following Description of the drawing in which a preferred embodiment is formed according to the invention {^! removal device has been shown schematically in the drawing show

Fig. 1 shows a closed blood collection device with a filled anticoagulant, as it is from Manufacturer is delivered in view;

F i g. 2 the same blood collection device when put on the cannula in longitudinal section;

F i g. 3 the same blood sampling device in section along the line 1II-III in FIG. 2;

4 shows the same blood sampling device after the blood has been taken with the lid closed and the one broken off View of the piston rod as it is being sent to the laboratory.

A blood collection device consists of a cylinder 1 open at one end, an inserted and & 5 airtightly displaceable piston 2 and a cover 3 which can be inserted into the opening. The piston 2 is over a predetermined breaking point 4 connected to a piston rod 5, which through a central opening 6 in the partial closed end of the cylinder 1 is led out

The lid 3 engages with a shoulder 7 in the opening of the cylinder 1 and has in its transverse wall 8 an eccentrically arranged connection piece 9 for a cannula 10. The cannula 10 engages over the connecting piece 9 with a connecting cone 11.

In the connection piece 9 of the cover 3 is from the inside ago a plug 12 is inserted which engages with a cone 13 in the capillary of the connecting piece 9 and with a collar 14 of the transverse wall 8 rests on the inside. The stopper 12 has at its upper end a release pin 15 which protrudes from the connecting piece 9. The plug 12 is at its lower end provided with a mounting pin 16 which is flush with the edge when the collar 14 is in contact with the transverse wall 8 of the approach 7 on the cover 3 completes

As shown in FIG. 1 has been shown, pre-assembled by the manufacturer and contains a liquid anticoagulant 17. The plug 12 is innei; into the lid 3 been used before this after the dosing of the Anticoagulant 17 has been placed on the cylinder 1 The connection piece 9 is more like a cap 18 closed, in which the release pin of the stopper 12 can engage without contact. On the cover 3 is a another cap 19 molded with a thin ribbon, which is later used to close the connecting piece 9 can be demolished.

To take blood, first the cap 18 is removed and then the sterile cannula 10 is put on When the connecting cone 11 of the cannula 10 is pushed onto the connecting piece 9, the stopper 12 is with it his release pin 15 pushed out of the connecting piece 9 and falls into the cylinder 1 or the Piston 2 in. The blood flowing into the cylinder 1 when the piston 2 is pulled out mixes with it Anticoagulant 17 and also washes around the stopper 12 in the process.

When the blood sample has been taken, the piston rod 5 can break off at the predetermined breaking point 4 as shown in FIG. 4 has been shown. After removing the cannula 10, the connecting piece 9 closed with the torn off cap 19. The stopper 12 is then in the blood sample in the cylinder 1. In The blood sampling device can then take this final state to the laboratory for subsequent examination sent.

List of reference symbols

1 cylinder

2 pistons

3 lids

4 predetermined breaking point

5 piston rod

6 central opening

7 approach

8 bulkhead

9 connection pieces

10 Kanü'-i

11 connection cone

12 plugs

13 cone

14 federal government

15 release pin

16 Montaj,? Cones

17 anticoagulants

18 cap

19 cap

1 sheet of drawings

Claims (5)

Patent claims: 1. Blood collection device with a cylinder open at one end and an airtight therein displaceable piston, the piston rod in a central opening of the partially closed other end of the cylinder is guided and removable, and with one removable in the open end of the cylinder used cover, which has a pierced connection piece on its transverse wall for attaching a cannula, characterized by one in the connecting piece (9) of the lid (3) from the inside insertable stopper (12) with a release pin (15) from the Connection piece (9) protrudes 2. Blood sampling device according to claim 1, characterized in that the stopper (12) with a cone (13) engages in the connection piece (9) and with a collar (14) or approach of the Inside of the transverse wall (8) of the lid (3) rests 3. B! I «removal device according to the claims 1 and 2, characterized in that the stopper (12) has a mounting pin at its inner end (16) which has the inner end of a projection (7) of the cover (3) in the inserted position ends flush 4. Blutentnahmevorrichiung according to claims 1 to 3, characterized in that the connecting piece (9) is closed with a cap (18) until use, in which the release pin (15) of the stopper (12) protrudes without contact 5. Bluüntnahmvorrichtung according to claims 1 to 4, characterized gckennzc '^ hnet that the stopper (12) is made of a plastic whose specific gravity is greater than d: s of blood